scholarly journals The role of water conservation strategies and benchmark ecotopes for increasing yields in South Africa’s semi-arid croplands

Water SA ◽  
2019 ◽  
Vol 45 (3 July) ◽  
Author(s):  
Malcolm Hensley ◽  
Pieter AL Le Roux ◽  
J Jacobus Botha ◽  
Leon D Van Rensburg
Keyword(s):  
Water Conservation ◽  
New Technologies ◽  
Rainwater Harvesting ◽  
Arable Land ◽  
Daily Rainfall ◽  
Crop Productivity ◽  
Conservation Strategies ◽  
Cumulative Probability ◽  
Study Results ◽  
Semi Arid

Recently published results regarding South Africa’s cropping potential show that about one third of the arable land is of low potential, located mainly in semi-arid areas, with the main problem being water shortage.  This is therefore an appropriate time to review priorities and procedures, for selecting benchmark ecotopes to represent marginal areas, and for research needs with regard to water conservation strategies to mitigate the problems of low yields.  Relevant international principles encapsulated in the words agro-ecology, sustainability and socio-economic conditions, are discussed. Relevant new technologies are described, namely: digital soil mapping that will facilitate the identification of benchmark ecotopes; a stochastic procedure to predict rainfall intensity data from daily rainfall that will facilitate runoff predictions; a crop yield cumulative probability procedure that enables sustainability to be described quantitatively. As a case study, results from a successful field experiment using the infield rainwater harvesting production technique on benchmark ecotopes in a semi-arid area, inhabited by subsistence farmers, are presented.  The objectives of the study, procedures used and the method of expressing the results are recommended as guidelines for contributing towards mitigating the problem of low crop productivity across a large portion of the arable area in South Africa.

scholarly journals Spatiotemporal Analysis of Potential Impact of Soil Erosion on Maize and Groundnuts Yield in Northern Ghana

2021 ◽  
Vol 5 (2) ◽  
pp. 486-493
Author(s):  
Wilson Agyei Agyare ◽  
Eliasu Salifu
Keyword(s):  
Soil Erosion ◽  
Water Conservation ◽  
Arable Land ◽  
Current Trend ◽  
Spatiotemporal Analysis ◽  
Crop Productivity ◽  
Potential Effect ◽  
Northern Ghana ◽  
Erosion Rates ◽  
North East

Abstract Soil erosion is a threat to the viability of arable land, which has a relationship with crop productivity. This study was carried out in the Northern, North-East and Savannah Regions of Ghana, which have a high agricultural potential. The study examined erosion-yield relationship by comparing estimated erosion rates with maize and groundnut yields in a GIS environment. The study also projected soil erosion and determined its potential effect on the yield of maize and groundnuts. The soil erosion rates were found to be 4.2 t ha-1y-1, 5.1 t ha-1y-1 and 7.1 t ha-1y-1 for the Northern, North-East and Savannah Regions respectively. Projections for the next 10 years showed that, soil erosion will averagely increase by about 12 %, which could reduce the yield of maize and groundnut by 21 % and 16 % respectively by the year 2031, should the current trend continue. The study also found out that crop (maize and groundnut) yield per land area is relatively lower in areas severely affected by soil erosion. Farmers in the study area and areas of similar ecology must be encouraged to adopt Soil and Water Conservation (SWC) strategies to enhance and sustain productivity.

scholarly journals Perception-based Assessment of Ecosystem Services of Abijata-Shalla National Park Wetlands in the Central Rift Valley of Ethiopia

2022 ◽  
Author(s):  
Denbel Bedo ◽  
Abate Mekuriaw ◽  
Amare Bantider
Keyword(s):  
Ecosystem Services ◽  
National Parks ◽  
Water Conservation ◽  
Group Discussion ◽  
Arable Land ◽  
Household Survey ◽  
Mitigation Measures ◽  
Conservation Strategies ◽  
Domestic Water ◽  
Water Abstraction

Abstract Abijata-Shalla Park was established as one of Ethiopia's national parks to safeguard wetlands and ecosystem services (ESs). Some of the ESs that are offered by the wetlands are currently depleting and disappearing rather than being protected. Understanding the drivers behind these changes can help individuals and policymakers design mitigation measures. The objective of this case was to assess ESs and the drivers of change with highlighting on the Abijata wetland. In addition to a household survey and group discussion, personal interviews and field observation were employed to collect data. Using these data, the various ESs were assessed and ranked from 1-10 according to local perception. Grading scales such as very high (−2), high (−1), neutral (0), low (+1), and very low (+2) were employed to analyse the drivers of ESs change. Analyses of the study revealed that some of the ESs, including fish, papyrus, water reeds, hunting and spiritual services, existed before 1991, but have since disappeared from the site. Twenty ESs are available; 11 services pertain to provisioning, followed by 4 regulating, 3 cultural and 2 supporting services. Wetland for cultivation ranked highest, followed by domestic water supply and pasture. All services, with the exception of arable land and pasture, are on the decline. Water abstraction is the primary driver of ESs change, followed by population growth and deforestation. The park existed as a "paper park." Water withdrawals from the Ziway-Shalla sub-basin should be restricted. Instead, focus on water conservation strategies to make better use of abstracted water.

scholarly journals Achievements, challenges and opportunities of rainwater harvesting in the Ethiopia context: a review working paper No. 1

2021 ◽  
Author(s):  
Negash Tessema Roba ◽  
Asfaw Kebede Kassa ◽  
Dame Yadeta Geleta ◽  
Birhanu Kindshih Hishe
Keyword(s):  
Water Conservation ◽  
Crop Production ◽  
New Technologies ◽  
Rainwater Harvesting ◽  
Smallholder Farmers ◽  
Conservation Tillage ◽  
Low Cost ◽  
Lessons Learned ◽  
Household Food Security ◽  
Water Supply Systems

Abstract Rainwater harvesting (RWH) is a novel way for developing countries to construct and maintain long-term water supply systems. As a result, this review article draws on actual findings and lessons learned from various places in Ethiopia to assess the country's achievements and opportunities when it comes to RWH, as well as to guide future alternatives toward its sustainability. RWH acts as a tie throughout the rainy season's dry spells, benefiting human and livestock consumption as well as crop production through irrigation. So, for the victory of well-organized rain water collection, watershed treatment, seepage and evaporation control, soil and water conservation, conservation tillage, and integration of low-cost water lifting techniques and family drip systems should all be feasible. Given that the country is not further modernized, it has ancient dated experiences on the operation and exploitation of RWH systems. Aside from financial inadequacies, historical and political instability, lack of understanding among farmers, and resistance to new technologies, the country has opportunities and has made some progress on rainwater harvesting systems. In general, rainwater harvesting could enable smallholder farmers to diversify their crops, thereby enhancing household food security, dietary status, and economic return. In addition, the much-needed green revolution and climate change adaptations should combine rainwater harvesting ideas with agronomic principles in the country. More work is needed to strengthen indigenous practices and share best practices to a larger scale.

scholarly journals Local regulations on alternative water sources: greywater and rainwater use in the Metropolitan Region of Barcelona

2014 ◽  
pp. 87 ◽  
Author(s):  
Laia Domènech ◽  
Maria Vallès
Keyword(s):  
Water Conservation ◽  
Social Acceptance ◽  
New Technologies ◽  
Rainwater Harvesting ◽  
Water Cycle ◽  
Water Sources ◽  
Metropolitan Region ◽  
North East ◽  
Alternative Water ◽  
Alternative Water Sources

Alternative water resources are gaining momentum in Catalonia (north-east Spain) in an effort to promote water conservation and build resilience against drought episodes. Since 2002 more than 50 municipalities (summing up more than 1.3 million people) have approved a water saving ordinance that involves the installation of rainwater harvesting and/or greywater reuse systems in new buildings. These new technologies trigger important transformations in the existing water cycle including institutional and social changes related with water decentralization. Drawing on interviews with local environmental managers and survey data from rainwater harvesters and greywater users, this paper analyses the social and technical learning generated during the implementation of the regulations and the main impediments and barriers that need to be overcome to control health risks and promote social acceptance of these alternative water sources.

scholarly journals A Stochastic Model to Predict Flow, Nutrient and Temperature Changes in a Sewer under Water Conservation Scenarios

Water ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1187 ◽  
Author(s):  
Olivia Bailey ◽  
Ljiljana Zlatanovic ◽  
Jan Peter van der Hoek ◽  
Zoran Kapelan ◽  
Mirjam Blokker ◽  
...  
Keyword(s):  
Water Conservation ◽  
Rainwater Harvesting ◽  
Transport Model ◽  
Oxygen Demand ◽  
Conservation Strategies ◽  
Nutrient Concentrations ◽  
Quality Model ◽  
Solids Transport ◽  
Wastewater Quality ◽  
Specific Discharge

Reducing water use could impact existing sewer systems but this is not currently well understood. This work describes a new flow and wastewater quality model developed to investigate this impact. SIMDEUM WW® was used to generate stochastic appliance-specific discharge profiles for wastewater flow and concentration, which were fed into InfoWorks® ICM to quantify the impacts within the sewer network. The model was validated using measured field data from a sewer system in Amsterdam serving 418 households. Wastewater concentrations of total suspended solids (TSS), chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN) and total phosphorus (TPH) were sampled on an hourly basis, for one week. The results obtained showed that the InfoWorks® model predicted the mass flow of pollutants well (R-values 0.69, 0.72 and 0.75 for COD, TKN and TPH respectively) but, due to the current lack of a time-varying solids transport model within InfoWorks®, the prediction for wastewater concentration parameters was less reliable. Still, the model was deemed capable of analysing the effects of three water conservation strategies (greywater reuse, rainwater harvesting and water-saving appliances) on flow, nutrient concentrations, and temperature in sewer networks. Results show through a 62% reduction in sewer flow, COD, TKN and TPH concentrations increased by up to 111%, 84% and 75% respectively, offering more favourable conditions for nutrient recovery.

scholarly journals Preliminary Model-Based Evaluation of Water Conservation Strategies in a Semi-Arid Urban Zone

Land ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 101
Author(s):  
Marcelino Antonio Zúñiga-Estrada ◽  
Liliana Lizárraga-Mendiola ◽  
Carlos Alfredo Bigurra-Alzati ◽  
Sergio Esteban Aldana-Alonso ◽  
Jorge Santiago Ramírez-Núñez ◽  
...  
Keyword(s):  
Environmental Protection Agency ◽  
Water Conservation ◽  
Urban Areas ◽  
Conservation Strategies ◽  
Storm Event ◽  
Storm Events ◽  
Preliminary Model ◽  
Field Assessment ◽  
Preliminary Study ◽  
Semi Arid

The U.S. Environmental Protection Agency stormwater management model was applied to a semi-arid urban micro watershed. The sub-catchment’s current features were modeled as scenario A, while the insertion of a set of LID technologies (rain barrels, bioretention cells, permeable pavement, and infiltration trenches) was represented as scenario B. A third scenario (C), considering only the most feasible LID technologies, was also modeled. All the scenarios were evaluated under two representative storm events (30 and 9 mm in two consecutive days, and 39 mm of rainfall in one day) occurred during the sampling performed in this study. Water quality was also simulated for a 30-mm storm event and compared against field assessment results after a real 30-mm storm event. Through the model, the inefficiency of current evacuation methods after 30- and 39-mm storm events was demonstrated. Simulation of scenario B showed that LID technologies could satisfactorily diminish peak flows generated by the selected storm events as well as runoff-conveyed pollution, while the realistic scenario allowed a lower but satisfactory hydrological performance and almost the same runoff quality than scenario B. This preliminary study could contribute to spread awareness about the benefits of LID technologies in semi-arid urban areas of the developing world.

scholarly journals Assessing the Applicability of Low Impact Development Techniques in Arid and Semi-arid Regions

2021 ◽  
pp. 20-37
Author(s):  
Hadi Heidari ◽  
Mohammad Reza Kavianpour
Keyword(s):  
Water Conservation ◽  
Stormwater Management ◽  
Arid Regions ◽  
Rainwater Harvesting ◽  
Low Impact Development ◽  
Negative Consequences ◽  
Study Region ◽  
Climate Conditions ◽  
Harvesting Technique ◽  
Semi Arid

Low impact development (LID) techniques are increasingly used as a stormwater management strategy to maintain the hydrological conditions of developed areas and mitigate the negative consequences of stormwater runoff and nonpoint source pollution. Although LID techniques have been commonly used in moderate to humid areas, further information is needed on their effectiveness in semi-arid and arid regions. This study aims to examine and compare the effectiveness of LID techniques in arid and semi-arid climate conditions. First, a comprehensive study was conducted to rank LID techniques based on literature reviews while also incorporating different stakeholder priorities. Then, the city of Varamin, Tehran, Iran, was chosen as a low slope arid and semi-arid study region to assess the applicability of the best three high-ranked LID techniques using the storm water management model (SWMM). The results indicated that rainwater harvesting is the most effective technique in terms of stormwater quality and quantity management. The implementation of the rainwater harvesting technique across the case study is likely to decrease the average discharge, peak discharge, total volume, total runoff, and total suspended solids (TSS) by respectively 31.2%, 12.7%, 40.71%, 40.77% and 37.91%. Besides, rainwater tanks were projected to provide the water demands of home gardens during the five dry months, in addition to other domestic needs for water conservation objectives. The application of LID techniques in such water-limited regions can be useful for both stormwater management and water conservation.

scholarly journals Microbiological Health Risk Assessment of Water Conservation Strategies: A Case Study in Amsterdam

2021 ◽  
Vol 18 (5) ◽  
pp. 2595
Author(s):  
Agung Kusumawardhana ◽  
Ljiljana Zlatanovic ◽  
Arne Bosch ◽  
Jan Peter van der Hoek
Keyword(s):  
Risk Assessment ◽  
Health Risks ◽  
Water Conservation ◽  
Rainwater Harvesting ◽  
Water System ◽  
Infection Risk ◽  
Conservation Strategies ◽  
Quantitative Microbial Risk Assessment ◽  
Microbial Risk Assessment ◽  
Toilet Flushing

The aim of this study was to assess the health risks that may arise from the implementation of greywater reuse and rainwater harvesting for household use, especially for toilet flushing. In addition, the risk of cross connections between these systems and the drinking water system was considered. Quantitative microbial risk assessment (QMRA) is a method that uses mathematical modelling to estimate the risk of infection when exposure to pathogens happens and was used in this study to assess the health risks. The results showed that using rainwater without prior treatment for toilet flushing poses an annual infection risk from L. pneumophila at 0.64 per-person-per-year (pppy) which exceeds the Dutch standard of 10−4 pppy. The use of untreated greywater showed a risk that is below the standard. However, treatment is recommended due to the ability of P. aeruginosa to grow in the reuse system. Moreover, showering and drinking with cross-connected water has a high annual infection risk that exceeds the standard due to contact with Staphylococcus aureus and E. coli O157:H7. Several measures can be implemented to mitigate the risks such as treating the greywater and rainwater with a minimum of 5-log removal, closing the toilet lid while flushing, good design of greywater and rainwater collection systems, and rigorous plumbing installation procedures.

Sign in / Sign up

Export Citation Format

Share Document